A natural body of water may have a variation in the water temperature between the surface and the bottom. In a lake, for example, the water temperature may be divided into three zones, the epilimnion, the thermocline, and the hypolimnion. The epilimnion, which is the zone of water generally proximate the water surface, generally has a warmer water temperature than the other zones. The water temperature may be generally evenly distributed throughout the epilimnion, as the water in the epilimnion may be generally well mixed by turbulence resulting from wind and wave action. The zone adjacent the bottom is the hypolimnion. Water in the hypolimnion is colder than water in the epilimnion. A transition zone known as the thermocline separates the epilimnion from the hypolimnion. The water temperature in the thermocline is characterized by a water temperature gradient as the water temperature in the thermocline varies from the warm water temperature of the epilimnion to the cool water temperature of the hypolimnion.
A lake or reservoir may have other water temperature structures depending upon the time of the year and the climate of the region. Rivers may have various water temperature structures, and the sea may have various thermal strata, water temperature currents, and other thermal structures.
FIG. 1 illustrates a lake divided into an epilimnion, a thermocline, and a hypolimnion. The corresponding water temperature profile is shown with the z-coordinate indicating depth from the surface and T indicating the water temperature corresponding to the depth. As illustrated in FIG. 1, the thermocline is marked by a steep water temperature gradient. Fish, in this illustration, are gathered about the thermocline. The water temperature profile may be measured by measuring the water temperature at various depths between the water surface and the bottom. For example, temperatures T1, T2, T3 are measured at depths z1, z2, z3 to determine a portion of the water surface temperature profile illustrated in FIG. 1.
Various species of fish may live in a preferred water temperature range, which may be quite limited. Some species of fish travel along the thermocline or break or will prefer other zones or water temperature structures. Accordingly, in order to fish effectively for a certain species of fish, it may be important to locate the thermocline or other strata having the water temperature the that species prefers. Thus, various probes have been devised to measure the water temperature profile. Probes for the measurement of the water temperature profile may have other oceanographic, limnological, or other scientific as well as industrial uses or other usages.
In various aspects, probes for the measurement of the water temperature profile may include sensitive electronics housed within a chamber inside a housing. The housing may be constructed in various ways to seal about the chamber while allowing access to the chamber in order to allow for replacement of the power supply or repair or replacement of other components housed within the chamber. In various aspects, the housing may include various components threadedly connected to one another and with various gaskets, seals, and so forth interposed between the components to seal the chamber from water penetration. Access to the chamber may be obtained by taking apart the threaded connections. Access may be in the form of a cover plate removeably secured about the housing, and various gaskets, seals, and so forth may be included to seal the cover plate. Such threading, gaskets, seals, cover plates, and so forth may be expensive to manufacture and may be prone to leakage thereby resulting in failure of the probe.
Accordingly, there is a need for improved probes for the measurement of water temperature profiles, as well as related processes for the manufacture thereof.